New research has revealed a steady increase in the number of donor eggs used for in vitro fertilization in the US between 2000 and 2010, with improved birth outcomes. This is according to a study published in JAMA.

Researchers from the Emory School of Medicine in Atlanta, GA, used data from the Center for Disease Control and Prevention’s National Assisted Reproductive Technology (ART) Surveillance System (NASS). This system includes data on more that 95% of all in vitro fertilization (IVF) cycles performed in the US.

The researchers analyzed the data to determine whether there has been an increase in the annual number of donor oocyte cycles during the 10-year period, and whether there has been improved perinatal outcomes.

Good perinatal outcome was defined as a single live-born infant delivered at 37 weeks or later, and weighing 5.5 pounds or more.

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Researchers say there has been a steady increase in the number of IVF donor between 2000-2010, as well as an increase in good perinatal outcomes.

Results of the analysis revealed that in over 443 clinics in the US (representing 93% of all US fertility centers), the annual number of donor oocyte cycles had increased from 10,081 in 2000 to 18,306 in 2010.

The percentage of these cycles that involved frozen embryos or oocytes, compared with fresh, also increased, from 26.7% in 2000 to 40.3% in 2010. This involved elective single-embryo transfers, which increased from 0.8% in 2000 to 14.5% in 2010.

Furthermore, good birth outcomes significantly increased from 18.5% in 2000 to 24.4% in 2010.

The average age for donors remained at 28-years-old throughout the 10-year period, while the average age for recipients stayed at 41-years-old.

The researchers note that although the positive trend of good perinatal outcomes was consistent with an increased tendency toward elective single-embryo transfer, the rate of twin delivery among donor recipients remained high at 37%, suggesting there is “room for improvement.”

They study authors add:

The high percentage of multiple births among donor oocyte recipients […] suggests potential for further improvement in perinatal outcomes if elective single-embryo transfer is used more frequently among donor oocyte cycles.”

The use of donor oocytes is an increasingly common treatment for infertile women with diminished ovarian reserve, but the researchers say the study shows the likelihood of successful birth outcome seems to be independent of recipient age.

“To maximize the likelihood of a good perinatal outcome, the American Society of Reproductive Medicine recommendations suggesting transfer of a single embryo in women younger than 35 years should be considered,” say the researchers.

In a comment piece linked to the study, Evan R. Myers of the Department of Obstetrics and Gynecology at Duke University School of Medicine says the finding that recipient age was not independently associated with poor perinatal outcomes is “both clinically reassuring and biologically intriguing.”

“Because the risk of maternal complications increases with age, one would expect an age-related association with earlier gestational age at delivery or smaller birth weight,” he adds.

“The lack of an observed association suggests the possibility that use of donor oocytes may reduce the risk of some pregnancy complications in women who become pregnant through Assisted Reproductive Technology (ART) compared with the use of autologous oocytes.”

The researchers note that additional studies are warranted in order to understand how race/ethnicity, infertility diagnoses and day of embryo culture can affect birth outcomes, in order to create preventive measures to increase the chances of good perinatal outcomes.

Finally, the study authors say more detailed information is needed for potential donors and recipients as well as clinicians:

Given the increasing trend of oocyte donations, the inclusion of more detailed information about donor risks, such as ovarian hyperstimulation syndrome, in the NASS will be useful for monitoring the safety of donor cycles.”

Medical News Today recently reported on a study detailing a new technique to induce egg growth in infertile women.